The proposed series of experiments is designed to elaborate the ways in which hormones might affect aggression through affecting related behaviors. Further, this project will test the relationships among the hormonal bases of aggression, fearfulness, arousability and sexual behavior. The research strategy to be used includes manipulation of either adrenocortical or testicular functioning and observing the effects of these manipulations on these behaviors as determined through the use of a "behavioral screen." Following the initial two experiments which use this strategy, attempts will be made to modify individual behaviors with particular hormonal manipulations, while not affecting the other behaviors measured. In this way, it is hoped that we shall be able to determine whether hormones affect aggression directly or whether they affect aggression through their known affect on related behaviors.